WPR13FA010

The pilot’s flight in dark night conditions with no visual reference and his subsequent spatial disorientation.

During a night cross-country flight, the airplane collided in the unpopulated desert located in between the departure and destination airports. The non-instrument-rated pilot had amassed an estimated 185 hours of total flight experience, of which 7.3 hours were conducted in nighttime conditions. Although the pilot had made this trip twice before, those flights were not conducted in dark night conditions. For the first 30 minutes after departure, radar returns for the flight were uniformly spaced and at uniform altitudes, with the track was consistent with a route of flight toward the destination airport. About 4 minutes before the end of the data, radar returns indicate a period consistent with the airplane making a series of turns with fluctuations in altitude. The maneuvering and altitude variations were inconsistent with the intended route of flight, and along with the pilot's inexperience in night time conditions, he likely experienced the effects of spatial disorientation as the accident occurred in an area devoid of visual references. Ground scar analysis, impact signatures, and wreckage fragmentation patterns disclosed that the airplane impacted terrain in a slightly nose-low attitude with high forward velocity. A review of the pilot's daily work activities revealed that he had not obtained his normal amount of rest before the accident and was likely fatigued; however, the effect the fatigue would have had on his operation of the airplane could not be determined. A postaccident examination of the airframe and engine revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

The wreckage was recovered and transported to the facilities of Air Transport, Phoenix, Arizona, for a detailed examination. Present to the examination was a Safety Board investigator, as well as a representative from both Piper Aircraft and Textron Lycoming. Airframe The left wing separated into two major portions with the inboard half attached to remnants of the lower center fuselage section. The left flap remained partially attached to the inboard wing section. The left aileron had separated from the outboard half of the wing. The aileron bellcrank was separated from the wing structure. Both the primary and balance cable ends remained attached to the bellcrank, which exhibited deformation on its respective arms. The right wing experienced extensive fragmentation, and the entire right wing had separated from the fuselage at the wing root. The outboard wing tip section exhibited diagonal accordion type crushing from the leading edge running inboard. The aileron surface separated from the wing, and sustained impact damage. The flap surface was broken at about mid span, and separated from the wing. The aileron bellcrank remained attached to the wing structure. Both the aileron primary and balance cables ends remained attached to the bellcrank, which exhibited deformation on its respective arms. The flap torque tube assembly separated from the center fuselage section. The ratcheting detents of the flap lever were bent and separated. Due to the damage sustained, the position of the flaps could not be determined. The empennage section of the aircraft sustained extensive ground impact damage and had sustained major crush damage. The empennage section separated from the cabin area. The empennage enclosure skins were ripped and torn into several sections. The rudder remained attached to the vertical stabilizer, which was still attached to the aft section of the fuselage. The stabilator was still attached to the tail section. Both rudder cables remained attached to the rudder horn. Both stabilator cables remained attached to the balance weight tube assembly. The stabilator trim jack screw exhibited 7 exposed threads with 5 threads being neutral and 16 threads corresponding to a full nose up trim setting. The fuel selector valve (located on the left side of the cabin in front of the pilot's seat) had separated from the airplane. The valve handle was broken and separated from the valve assembly. The valve was disassembled, and found to be in the 'off' position. The fuel gascolator assembly remained attached to the selector fuel line. Engine The engine mount support tubes separated between the engine and firewall separating the engine from the airframe. A majority of the crankcase was intact, but the aft portion consisting of accessory drive gears had mostly broken away. As a result of the crush damage, crankshaft rotation could not be accomplished. To facilitate further internal examination, holes were drilled through the top of the engine case material in-line with the rotational plane of each connecting rod. A lighted borescope was inserted to visualize each connecting rod, crankshaft, and camlobes at the respective cylinder position. There was no evidence of lubrication depravation or contamination found. The crankshaft and attached connecting rods showed no evidence of heat distress. The camshaft was intact, and each of the camlobes did not appear misshapen. According to the Lycoming representative, the combustion chambers of the cylinders remained undamaged by any foreign object ingestion. The gas path and combustion signatures observed at the spark plugs, combustion chambers, and exhaust system components displayed coloration consistent with normal operation. The spark plugs were removed, examined, and photographed. The spark plug electrodes remained mechanically undamaged, and according to the Champion Spark Plugs Check-A-Plug chart AV-27, the spark plug electrodes displayed coloration consistent with normal operation. Both magnetos, which were sheared from the engine, were examined. The left magneto impulse coupler drive was found intact and secure. The drive functioned normally during hand rotation of the drive. The magneto produced spark at the four leads during hand rotation of the drive. The right magneto was fragmented and sustained damage that rendered the unit inoperative and therefore, could not be functionally tested. The accessory gears including the crankshaft gear, bolt, and dowel were intact and remained undamaged by any pre impact malfunction. The propeller had separated from the engine crankshaft. The propeller blades displayed leading edge gouging, torsional twisting, chordwise striations across the cambered surface, and trailing edge "S" bending. The signatures were consistent with the absorption of rotational forces applied at the crankshaft at the time of impact. There was no evidence of any preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. The Pima County Sherriff's Office Pima County, Arizona, completed an autopsy on the pilot. The FAA Toxicology and Accident Research Laboratory performed toxicological testing on specimens of the pilot. The results of the analysis of the pilot's specimens revealed no evidence of ethanol or drugs. The closest aviation weather observation station was located at Tucson International Airport, about 35 miles southeast of the accident site, at an elevation of 2,650 feet mean sea level (msl). A routine aviation weather observation (METAR) was issued 15 minutes prior to the accident, at 1853, and reported the following conditions: wind from 360 degrees at 3 knots; visibility 10 statute miles; clear sky conditions; temperature 27 degrees Celsius; dew point -3 degree Celsius; and altimeter setting of 30.01 inches of mercury (inHg). Data from the United States Naval Observatory indicated that the phase of the moon was waning crescent with 1-percent of the Moon's visible disk illuminated. The sunset occurred at 1750, and the end of civil twilight was 1815. The Piper PA-28-151, serial number 28-7515119, was manufactured in 1974, and purchased by the pilot in May 2011. The airplane's maintenance records revealed that the last annual inspection was performed on August 1, 2012. An estimated airframe total time of 4,657.2 hours at the time of the accident was determined by adding the pilot's total flight time since the last maintenance performed. The airplane was equipped with the originally installed four-cylinder Lycoming O-360-E3D engine, serial number L-39304-27A. According to the logbooks, last recorded maintenance on the engine was performed during the annual inspection, and it was noted that at that time, it had accumulated about 90 hours since the last major overhaul. Fuel receipts located within the wreckage indicated that while in Benson, the pilot added about 28 gallons of fuel at 1216, and then added about 14 gallons at 1804. According to the Federal Aviation Administration (FAA) Airman and Medical record files, the 57 year old pilot held a private pilot certificate with an airplane rating for single-engine land, which was issued on April 22, 2012. The pilot's most recent third-class medical certificate was issued on September 08, 2010, containing the limitation that he must wear corrective lenses for near and distant vision. There were no records of a more recent medical examination for a new medical certificate. The pilot's flight records were found in the wreckage, and consisted of a bound logbook dated from April 10, 2011, to September 19, 2012. The summation of flight hours from the logbook revealed that the pilot had accumulated 185 hours of total flight experience, primarily all of which were flown in the accident airplane. The logs additionally disclosed that he had accrued 7.3 hours of flight time in nighttime conditions. Based on the airport identifiers listed in